1. Field of The Invention
The present invention relates to a socket for electrical parts or components for detachably holding an electrical part such as a semiconductor device (hereinafter, referred to as an IC (Integrated Circuit) package), and also relates to a method of assembling the socket.
2. Description of The Prior Art
In a known art, as a conventional xe2x80x9csocket for electrical partsxe2x80x9d of this kind, there is provided an IC socket for detachably holding an IC package as xe2x80x9celectrical partxe2x80x9d.
The IC socket is provided with a socket body and a top plate disposed on the socket body so that the IC package is mounted on the top plate. The IC socket is also provided with contact pins detachably contacted to terminals of the IC package and a slide plate arranged between the top plate and the socket body so as to be permitted to horizontally slide. Moreover, an upper operation member is disposed to the socket body so as to be movable vertically (upward and downward) with respect to the socket body.
When the upper operation member is moved downward, the slide plate located at an initial position is horizontally slid so as to elastically deform the contact pins, and a contact portion formed on an upper end of each of the contact pins moves away from an insertion area of the terminals of the IC package. After the contact pin moves away from the insertion area, the IC package is mounted on the top plate, and the upper operation member is moved upward so that the slide plate returns to the initial position, thereby releasing a pressing force against the contact pins. The release of the pressing force causes the contact pin to return an initial position by an elastic force so that contact portion of each of the contact pins contacts to each of the terminals of the IC package so as to be electrically connected thereto.
In these structures of the conventional IC socket, installation and removal of the IC package have been carried out only by sliding horizontally the slide plate without applying insertion and extraction force, making it possible to extremely improve efficiency of the installation and removal of the IC package.
However, in the conventional socket described above, in order to secure a contact pressure of the contact portion of each of the contact pins to each of the terminals of the IC package, it is necessary for each of the contact pins to have comparatively large rigidity. In a case where the contact pins must be arranged on the socket body so that each of the pitches (spaces) between the respective contact pins is narrow, it is necessary to use fine contact pins. Because the fine contact pin does not have sufficient rigidity, there is the possibility that a suitable contact pressure of the contact pin to the terminal of the IC package is not secured. In addition, in order to elastically deform the large number of contact pins each having large rigidity, there is a need of a large operating force for operating the upper operation member.
Furthermore, the contact portion of each contact pin must be arranged at a predetermined position so as to contact to each terminal of the IC package. However, since the contact pin, having long and thin structure, has a lower end disposed to the socket body and the upper end formed with the contact portion contacting to a solder ball, as the terminal of the IC package, a position of the contact portion is instable so that it is hard to arrange the contact portion of the contact pin to the predetermined position.
On the other hand, in this IC socket, the contact pins, which are arranged as an array on the whole, are pressed to fit in the socket body. The slide plate, the top plate and the like are successively laminated and arranged on an upper side of the contact pins.
Each of the plates is formed with through holes, and the upper end portions of the contact pins are inserted in the through holes, respectively.
However, in the conventional IC socket, when plate members, such as the slide plate, the top plate and so on, are assembled to the socket body, the respective upper end portions of the contact pins fitted in the socket body must be inserted in the respective through holes. Therefore, in a case where precision of the spaces between the respective upper end portions of the respective contact pins is deteriorated, it is very hard to carry out the insertion work of the respective contact pins, so that much time for carrying out the insertion work is required.
Especially, because the IC package is getting to rapidly small-sized so that the pitches between the respective terminals are getting to narrow, the pitches between the respective contact pins are getting to narrow. For this reason, the above problems caused by the insertion work of the contact pins are remarkably exposed.
The present invention is directed to overcome the foregoing problems.
Accordingly, it is an object of the present invention to provide a socket for electrical parts, which is capable of securing a reaction force (contact pressure) by using a thin contact pin and of operating the contact pin by using a small operating force.
It is another object of the present invention is to provide a socket for electrical parts, which is able to arrange a contact portion of a contact pin to a predetermined position.
It is a further object of the present invention is to provide a socket for electrical parts and a method of assembling the socket, which are capable of positioning front end portions of contact pins so that the front end portions thereof are aligned, thereby improving an assembly efficiency of an plate member of the socket.
These and other objects can be achieved according to the present invention by providing, in one aspect, a socket for an electrical part comprising:
a socket body having a mount portion on which an electrical part is mounted, the electrical part having terminals;
a number of contact pins arranged to the socket body and adapted to be contacted to or separated from the terminals of the electrical part, respectively;
a movable plate disposed to the socket body so as to be movable with respect to the socket body,
each of the contact pins having an elastic piece formed at a front end portion thereof with a contact portion, the contact portion being displaced in accordance with the movement of the movable plate so as to contact to the terminal of the electrical part, thereby being electrically connected thereto; and
a press means for pressing a middle portion of the elastic piece of the contact pin arranged to the socket body so as to elastically deform the middle portion thereof along a direction in that the contact portion are contacted to the terminal of the electrical part.
In a preferred embodiment of this aspect, the press means comprises a press plate having press holes in which the middle portion of the elastic piece is inserted, the press plate being mounted on the socket body, while the middle portion of the elastic piece is inserted in the press hole and the press plate holes pressing the middle portion of the elastic piece so as to elastically deform the middle portion thereof.
The press member is detachably mounted on the socket body or mounted on the socket body integrally.
In another aspect, there is provided a socket for an electrical part comprising:
a socket body having a mount portion on which an electrical part is mounted, the electrical part having terminals;
a number of contact pins arranged to the socket body and adapted to be contacted to or separated from the terminals of the electrical part, respectively;
a movable plate disposed to the socket body so as to be movable with respect to the socket body,
each of the contact pins having a pair of elastic pieces, formed at front end portions thereof, with a pair of contact portions, each of the paired contact portions of the paired elastic pieces being opened or closed in accordance with the movement of the movable plate so as to clamp each of the terminals of the electrical part, thereby being electrically connected thereto; and
a press means for pressing a middle portion of each of the elastic pieces of each of the contact pins arranged to the socket body so as to elastically deform the middle portion thereof along a direction in which the paired contact portions are close to each other.
In a preferred embodiment of this aspect, the middle portions of the paired elastic pieces pressed by the press means are formed to be apart from each other at a first predetermined interval while the paired elastic pieces are not subjected to any external force and the contact portions of the paired elastic pieces are formed to be apart from each other at a second predetermined interval, the first predetermined interval being wider than the second predetermined interval.
Each of the paired elastic pieces is provided with a bent portion, the bent portions of the paired elastic pieces are formed at the respective middle portions thereof so that the respective middle portions are bent apart from each other, thereby forming vertex portions of the respective middle portions and said vertex portions of the bent portions are pressed by the press means, respectively. The paired elastic pieces are formed at lower ends with a base portion so that the paired elastic pieces are integrated by the base portion and the base portion is bent so that the paired elastic pieces are opposite to each other. The paired elastic pieces are formed at lower ends with a base portion so as to be integrated by the base portion, each of the contact pins is provided with a solder tail portion extending from the base portion so as to be connected to a printed circuit board and the solder tail portion is formed so that a center line between the paired elastic pieces coincides with a center line of the solder tail portion.
The press means comprises a press plate having press holes in which the middle portions of the elastic pieces are inserted, the press plate being mounted on the socket body, while the middle portions of the elastic pieces are inserted in the press holes, respectively, and the press plate holes presses the middle portions of the elastic pieces so as to elastically deform the middle portions. The press member is detachably mounted on the socket body or mounted on the socket body to be integral.
According to the above aspect of the present invention, because the press means is provided for pressing a middle portion of the elastic piece of the contact pin arranged to the socket body so as to elastically deform the middle portion thereof along a direction in that the paired contact portions are close to each other, it is possible to set displacement amount (press force, pre-load force) for elastically deforming the elastic pieces as desirable amount, thereby setting the contact pressure of the paired contact portions of the contact pin with respect to the terminal. Furthermore, since the contact pins each having a narrow width needless of using contact pins each having large rigidity becomes usable, it is possible to produce the socket having a structure in which each of the pitches between the respective contact pins is narrow and to make small the operation force applied to the contact pins by means of the movable plate.
It is also possible to set the press force (pre-load force) at the paired contact portions large, as compared with a socket having a structure in which the elastic pieces are parallel to each other. Furthermore, since the base portion is bent so that the elastic pieces are opposite to each other, by pressing one plate member by a press working, it is possible to easily produce the contact pin. Since the contact pin is formed in a manner that the solder tail portion is bent at the close portion so that the center line of the elastic pieces coincides with the center line of the solder tail portion, in a case where, for example, the electrical part is carried by an automatic machine so as to be set on one of the sockets mounted on the printed circuit board, it is convenient to coincide both the center lines.
Furthermore, it becomes possible to easily change the pre-load force with respect to the contact pin by only exchanging the press plate to another one of press plates, in which each of another press plates is provided with press holes each having a diameter different from the diameter of each press holes of the press plate.
Since the press means is integrated with the socket body, it is possible to apply the press force (pre-load force) to the contact pin without increasing a number of parts.
In a further aspect of the present invention, there is provided a socket for an electrical part comprising:
a socket body having a mount portion on which an electrical part is mounted, the electrical part having terminals;
a number of contact pins arranged to the socket body and adapted to be contacted to or separated from the terminals of the electrical part, respectively;
a movable plate disposed to the socket body so as to be movable with respect to the socket body,
each of the contact pins having a pair of elastic pieces formed, at front end portions thereof, with a pair of contact portions, the paired contact portions being opened or closed in accordance with the movement of the movable plate so as to clamp the terminals of the electrical part, thereby being electrically connected thereto; and
a positioning member arranged close to each of the paired contact portions of each of the paired elastic pieces, each of the positioning members being clamped by the paired elastic pieces and adapted to locate the paired contact portions at a predetermined position.
In a preferred embodiment of this aspect, the socket further comprises a top plate mounted on the socket body, the mount portion being formed on the top plate, and the movable plate is arranged below the top plate.
The socket may further comprises a press means for pressing a middle portion of each of the elastic pieces of each of the contact pins arranged to the socket body so as to elastically deform the middle portion thereof along a direction in that the paired contact portions are contacted to the terminals of the electrical part, respectively.
The middle portions of the paired elastic pieces pressed by the press means are formed to be apart from each other at a first predetermined interval while the paired elastic pieces are not subjected to any external force, and the contact portions of the paired elastic pieces are formed to be apart from each other at a second predetermined interval, the first predetermined interval being wider than the second predetermined interval.
The paired elastic pieces are formed to be tapered towards the contact portion thereof so that the contact portions of the paired elastic pieces are close to each other.
According to the above aspect of the present invention, since a positioning member is arranged close to the paired contact portions of the paired elastic pieces so that the positioning members are clamped by each paired elastic pieces and adapted to locate the paired contact portions at a predetermined position, it is possible to position the contact portions at a predetermined position and to keep proper a positional relationship between the terminals and the contact portions. In addition, because the paired elastic pieces of the contact pin clamp the positioning member, it is possible to set a center of the contact portions.
Furthermore, since pressing means is provided for pressing a middle portion of each of the elastic pieces of the contact pin arranged to the socket body so as to elastically deform the middle portion thereof along a direction in which the paired contact portions are contacted to the terminals of the electrical part, respectively, it is possible to set displacement amount (pre-load force) for elastically deforming the elastic pieces as desirable amount, thereby setting the contact pressure of the paired contact portions of the contact pin with respect to the terminal. In addition, since the contact pin is supplied with the pre-load force, it is possible to make small the operation force applied to the contact pins by means of the movable plate. Furthermore, the contact pin is previously pressed with the paired contact portions to be close, and since the positioning portion is inserted between the paired contact portions, it is possible to prevent the paired contact portions from being interfered.
Still furthermore, the paired elastic pieces are not subjected to any external force, and since the first interval of the middle portions of the paired elastic pieces pressed by the press means are wider than the second interval of the paired contact portions, it is possible to set the pre-load force at the paired contact portions large, as compared with a socket having a structure in which the elastic pieces are parallel to each other.
In a further aspect of the present invention, there is provided a socket for an electrical part comprising:
a socket body having a mount portion on which an electrical part is mounted, the electrical part having terminals;
a number of contact pins arranged to the socket body as an array and pressed to fit in the socket body, each of the contact pins having a front end portion;
a plate member mounted on the socket body, the plate member having a number of holes into which the contact pins are inserted, respectively, the front end portions of the contact pins being contacted to or separated from the terminals of the electrical part, respectively; and
a positioning member disposed to the socket body to be movable along an extending direction of the contact pin, the positioning member having a number of positioning holes into which the contact pins are inserted, respectively,
wherein, after the contact pins are fitted in the socket body, the positioning member is moved towards the front end side of each of the contact pins so as to permit each of the front end portions of each of the contact pins inserted in each of the positioning holes to be located at a predetermined position.
In a preferred embodiment of this aspect, each of the contact pins has a pair of clamp pieces formed, at front end portions thereof, with a pair of contact portions, each of the paired contact portions clamping each of the terminals of the electric part, when the contact pins are pressed to fit in the socket body, each of the paired contact portions of each of the paired clamp pieces is opened, and each of the paired contact portions is elastically deformed towards a direction in that each of the paired contact portions is closed in accordance with the movement of the positioning member towards the contact end side of each of the contact pins.
The plate member is adapted to be movable with respect to the socket body, each of the contact portions of each of the paired clamp pieces being opened or closed in accordance with the movement of the plate member so as to clamp each of the terminals of the electrical part, thereby being electrically connected thereto.
The socket may further comprises a top plate having a number of through holes and mounted on the socket body so that the paired contact portions are inserted in the through holes of the top plate, respectively, the mount portion being formed on the top plate.
According to the above aspect of the present invention, since the positioning member is disposed to the socket body so as to be movable along an extending direction of the contact pin, when the contact pins are pressed to be fitted in the socket body, it is possible to arrange the positioning member at a position such that the contact pins are easily pressed. Furthermore, after the contact pins are fitted in the socket body, since positioning member is moved towards the front end side of each of the contact pins, it is possible to locate the front end portions of the contact pins at a predetermined position. Therefore, it is possible to easily carry out the arrangement work of the contact pins and to improve a precision of spaces between the paired contact portions.
As a result, it is possible to easily assemble the plate member to the socket body, and to make the spaces (pitches) of the paired contact portions narrow.
Furthermore, since the elastically deformation of the paired clam pieces towards the closing direction by the upward movement of the positioning member causes the contact pin to be subjected to a pre-load so that it is possible to secure a contact pressure with respect to the terminal of the electrical part. Furthermore, it becomes possible to use a clamp piece having low rigidity as the clamp piece itself, thus making it possible to provide the socket having a structure in which each of the pitches between the respective contact pins is narrow.
In a still further aspect of the present invention, there is provided a method of assembling a socket having a socket body for an electrical part, comprising the steps of:
preparing a positioning member having a number of positioning holes, a number of contact pins each of which has a pair of clamp pieces formed, at front end portions thereof, with a pair of contact portions, a plate member having a number of press portions and a top plate having a mount portion on which an electrical part is mounted and a number of through holes;
disposing the positioning member to the socket body so as to be movable with respect to the socket body; inserting the contact pins in the positioning holes so as to press the contact pins to fit in the socket body;
inserting each of the press portions of the plate member in each of spaces between the paired elastic pieces so as to arrange the plate member on the socket body, the plate member being slidable with the socket body, the paired contact portions of each of the paired elastic pieces being opened or closed in accordance with the movement of the plate member;
moving the positioning member towards the contact portion side of each of the contact pins so as to elastically deform the paired elastic pieces thereby closing the paired contact portions so that the press portions of the plate member are clamped by the paired contact portions, respectively; and
inserting the closed contact portions into the through holes of the top plate so as to arrange the top plate on the socket body.
According to this aspect, when the contact pins are pressed to be fitted in the socket body, since the paired clamp pieces are opened, it is possible to easily insert the press portion of the plate member in the paired clamp pieces, thereby improving assembling efficiency of the plate member to the socket body.
The nature and further characteristic features of the present invention may be made more clear from the following descriptions made with reference to the accompanying drawings.